请写一段代码,利用libjpeg库实现对图像的双边滤波处理。
时间: 2024-02-13 17:08:00 浏览: 100
这里给出一个简单的利用libjpeg库实现对图像的双边滤波处理的C语言代码示例:
```c
#include <stdio.h>
#include <stdlib.h>
#include <jpeglib.h>
#include <jerror.h>
#include <math.h>
// 定义双边滤波函数
void bilateral_filter(unsigned char *src_data, unsigned char *dst_data, int width, int height, int channels, int radius, double sigma_d, double sigma_r)
{
int window_size = 2 * radius + 1;
double *w_d = (double *)malloc(sizeof(double) * window_size * window_size);
double *w_r = (double *)malloc(sizeof(double) * window_size * window_size);
double weight_d, weight_r, weight_sum;
double pixel_value;
int offset, i, j, k, l, m, n;
int x, y, x1, y1, x2, y2;
int neighbor_x, neighbor_y;
int src_index, dst_index;
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
offset = (y * width + x) * channels;
weight_sum = 0.0;
pixel_value = 0.0;
for (i = -radius; i <= radius; i++) {
for (j = -radius; j <= radius; j++) {
x1 = x + i;
y1 = y + j;
if (x1 < 0 || x1 >= width || y1 < 0 || y1 >= height) {
continue;
}
x2 = x1 - x;
y2 = y1 - y;
weight_d = exp(-(x2 * x2 + y2 * y2) / (2.0 * sigma_d * sigma_d));
neighbor_x = src_data[(y1 * width + x1) * channels];
neighbor_y = src_data[(y1 * width + x1) * channels + 1];
neighbor_z = src_data[(y1 * width + x1) * channels + 2];
weight_r = exp(-(neighbor_x - src_data[offset]) * (neighbor_x - src_data[offset]) / (2.0 * sigma_r * sigma_r));
weight_r *= exp(-(neighbor_y - src_data[offset + 1]) * (neighbor_y - src_data[offset + 1]) / (2.0 * sigma_r * sigma_r));
weight_r *= exp(-(neighbor_z - src_data[offset + 2]) * (neighbor_z - src_data[offset + 2]) / (2.0 * sigma_r * sigma_r));
w_d[(j + radius) * window_size + (i + radius)] = weight_d;
w_r[(j + radius) * window_size + (i + radius)] = weight_r;
weight_sum += weight_d * weight_r;
pixel_value += weight_d * weight_r * src_data[offset + j * width * channels + i * channels];
}
}
dst_data[offset] = pixel_value / weight_sum;
dst_data[offset + 1] = pixel_value / weight_sum;
dst_data[offset + 2] = pixel_value / weight_sum;
}
}
free(w_d);
free(w_r);
}
// 主函数
int main()
{
struct jpeg_decompress_struct cinfo;
struct jpeg_error_mgr jerr;
FILE *infile;
JSAMPARRAY buffer;
int row_stride;
// 打开JPEG文件
if ((infile = fopen("input.jpg", "rb")) == NULL) {
fprintf(stderr, "can't open input file\n");
return 0;
}
// 初始化JPEG解压对象
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_decompress(&cinfo);
jpeg_stdio_src(&cinfo, infile);
jpeg_read_header(&cinfo, TRUE);
jpeg_start_decompress(&cinfo);
// 读取JPEG图像数据
row_stride = cinfo.output_width * cinfo.output_components;
buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo, JPOOL_IMAGE, row_stride, 1);
unsigned char *data = (unsigned char *)malloc(cinfo.output_width * cinfo.output_height * cinfo.output_components);
unsigned char *output_data = (unsigned char *)malloc(cinfo.output_width * cinfo.output_height * cinfo.output_components);
while (cinfo.output_scanline < cinfo.output_height) {
jpeg_read_scanlines(&cinfo, buffer, 1);
memcpy(data + row_stride * (cinfo.output_scanline - 1), buffer[0], row_stride);
}
// 关闭JPEG解压对象
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
fclose(infile);
// 对图像进行双边滤波
bilateral_filter(data, output_data, cinfo.output_width, cinfo.output_height, cinfo.output_components, 5, 10.0, 100.0);
// 将结果保存为JPEG文件
struct jpeg_compress_struct dstinfo;
struct jpeg_error_mgr dsterr;
FILE *outfile;
JSAMPROW row_pointer[1];
int dst_row_stride;
if ((outfile = fopen("output.jpg", "wb")) == NULL) {
fprintf(stderr, "can't open output file\n");
return 0;
}
dstinfo.err = jpeg_std_error(&dsterr);
jpeg_create_compress(&dstinfo);
jpeg_stdio_dest(&dstinfo, outfile);
dstinfo.image_width = cinfo.output_width;
dstinfo.image_height = cinfo.output_height;
dstinfo.input_components = cinfo.output_components;
dstinfo.in_color_space = cinfo.out_color_space;
jpeg_set_defaults(&dstinfo);
jpeg_start_compress(&dstinfo, TRUE);
dst_row_stride = dstinfo.image_width * dstinfo.input_components;
row_pointer[0] = (JSAMPROW)malloc(dst_row_stride);
while (dstinfo.next_scanline < dstinfo.image_height) {
for (int i = 0; i < dst_row_stride; i++) {
row_pointer[0][i] = output_data[dstinfo.next_scanline * dst_row_stride + i];
}
jpeg_write_scanlines(&dstinfo, row_pointer, 1);
}
jpeg_finish_compress(&dstinfo);
jpeg_destroy_compress(&dstinfo);
fclose(outfile);
// 释放内存
free(data);
free(output_data);
free(row_pointer[0]);
return 0;
}
```
需要注意的是,这里的双边滤波函数只支持处理RGB三通道图像,如果需要处理其他类型的图像,需要进行相应的修改。在使用时,需要将`input.jpg`和`output.jpg`替换为实际的JPEG图像文件名。
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